The basic research in this proposal will be conducted in the Mycobacteriology Lab at the Little Rock, VA Hospital, where DNA fingerprinting of M. tuberculosis was developed. In the proposed study, all of the Mycobacterium tuberculosis isolated from persons in Arkansas over a period of three years will be analyzed by a recently developed DNA fingerprinting method. Clinical and demographic data will be collected for each patient by the Tuberculosis Control Division of the Arkansas State Department of Health. The specific aims of the research proposal are as follows: 1. Determine the frequency if identical DNA fingerprint patterns among strains of M. tuberculosis when there is no known epidemiologic link. 2. Determine the percentage of tuberculosis in the general population that is due to reactivated infection. 3. Determine the extent of primary tuberculosis in residents and employees of prisons, nursing homes, hospitals and shelters for the homeless. 4. Determine the extent to which nursing homes, prisons, hospitals and homeless shelters are a source of M. tuberculosis infection of people that live and work outside these institutions. 5. Determine whether certain DNA fingerprint patterns are associated with specific clinical presentation of tuberculosis. 6. Develop a more refined M. tuberculosis fingerprinting technique using segments of DNA which are frequently found flanking the insertion sequence IS6110.